Telephonic apparatus



Nov. 15, 1938; J ,WHITE v 2,136,720

TELEPHONIC APPARATUS FiledMarch 20, 1956 2 Sheets-Sheet l Patented, Nov. 15, 1938 UNITED sT TEs PATENT OFFICE TELEPHONIC AFPARATUS Joseph C. Boston, Mass.; Alice White,

Boston, IMasa, executrix of said Joseph G.

Application March 20, 193 s rianvo; 69,789 '2'- (Jlaims; (c1.' 179-107 The main purposes of my invention-are:

1. To produce a very powerfulyet y'ei-yts nali .1! to the entireearpiece-unit when the current changes in the armature coil produce corresponding flux changes in the piston-amature,.causing the latter to vibrate in the permanent magnetic field, as described. 2i) This vibrating case movement, 'actingon all car surfaces in contact with the case, is transmitted by these surfaces to closely underlying mastoid bone areas and thence to the auditory f centers in the brain;

This combination of air conduction and bone conductionmeets the objection that by using a bone conduction device alone the eardrum, bonechain, etc., are not given necessary exercise and the defectiveness or hearing thereby naturally increases.

Other objectswill be pointed out below.

In the drawings Figure 1 is a top plan of a device embodying my inventlom' t Figure 2 is a bottom plan 01' the same, with the bottom member removed;

Figure 3 is a section on line 3-3 of Figure 1; t Figure 4 is a detail of one of the segmental members described below; Figure 5 is a partial side elevation of the easing of Figure 3;

Figure 6 isadetail ofthe pole pieces described below;

. Figure 7 is a partial section, similar to that of 5 Figure 3, but showing a microphonic attachment;

and

Figures 8 and 9 are wiring diagrams described below, the ear plug occupying a different rotary position from that it occupies in Figure 1.

Metal casing I has a bottom opening, 2 of'the is held to flanges l of the casing l by screws 5,

casing I having an opening 6 for the wires described below, the wires being clamped between the .top of said opening 6 and said plate 3.

' armature ll of iron form shown in Figure 2. Bottom coverplate 3,

Ringor cap member isthreaded tothe outber 'l and the top oi'flange 8' clamp between them the fibre washer ill, the metal disc ll, the-fibre washer l2 and the metal ring l3.

The metal disc or cover plate 9 is rotatable on stud li the latter being riveted to plate ll, plate I i being perforated at H", as indicateclin Figure 3, to provide orifices for the passage of sound waves to the brass sound channel. 9 of plate 9, said channel having a slit 9 to permit springing of said channel.

side of annular flange'fl oi casing Ring mem- Metal ring "cooperates with metal ring l3 to friotionaily hold in place the depending an nu .lar flange ii of stretch diaphragm 16, which is preferably very thin/said flange being formed by forcing the ring I! upwardly into ring l3 so as to bend the flange 15 at substantially a right angle, thus stretching the diaphragm to a desired tension and thus increasing its sensitivity. The flange i5 is clamped between ring l3 and ring l4, it being understood that this formation of flange I5 is done'before the severalparts above mentioned are clamped between member I and the top of flange 8.

To the diaphragm I6 is soldered, or otherwise secured, the head ll of a cylindrical pistonmaterial. t k

The head ll is sufficiently larger, transversely, than the opening in pole piece l8 to providethe proper path for the flux of thepermanent ring magnet is which is held in place by screw 20 (Figures Brand 9) which passes through pole piece 21 and engages the threaded hole 22 of segmental brass washer 23.

Coil 24 is wlthin'the magnet l9 and is held in place by pole pieces l8'and 2|. Screw 25 is mounted on pole piece 21 to adjust the lower air gap between the screw 25.and the cylindrical armature l'l. Pole; piece I8 is held in place by screw it! and pole piece 2| is held in place by screw 20.

or other suitable magnetic tipped, as shown, from about point 32 to the free end 33 with fairly soft rubber or its equivalent,

the rubber being applied by dipping the wire in straight condition into the rubber. Preferably I dip the wire, as from 32 to 33, by hand into the rubber compound and then hang the wire by the loop portion. The rubber which has run down becomes of substantially the form shown, that is, tapering toward end 33. and forming a globular covering for the free end of the wire. If desired, in order to increase the rubber coating and tip, I may dip several times, so that the covered wire will fit the ear of the particular user, the repeated diping resulting in a proportionately increased globular end portion relative to the remainder of the covering portion, the globular end, by my method, building up faster than the rest of the covering material. The rubber covered portion preferably engages the concha of the ear thereby holding the device very firmly in place without abrasion or irritation or any harmful effect.

In Figure '7, which represents an amplifier unit, the diaphragm and the parts below it and casing i a e the same as the corresponding parts in Figure 3. An annular head 34 of insulating material is held to case I by internally-threaded clamp ring 35. If the diaphragm I6 is not stretched, as shown, the upper surface in contact with carbon particles 35 is properly surfaced, as by gold plating or being carbonized. The carbon particles are held in place within head 34 and beneath carbon plate 36,'the latter being held by spring cap 31 which contacts carbon plate 36 at 38. In Figure 7 I have shown a diaphragm but any suitable vibrator may be used.

In Figure 8 the current flows in the primary circuit from battery 50 through wire i, microphone diaphragm 52 with its other microphonic elements53, wire 54, primary coil 55, wires 56, 51, 58, 59 to the variable resistance 60 and back to the battery. The changing current in the primary circuit induces an alternating current in the secondary circuit which current flows from secondary coil 6i through'wire 62, 63, 64 and around the coil in the direction indicated by the arrows (in full lines) and then back through wires 85, 86 'and 61 to the secondary coil 8|. Wires 63 and 66 are suitably held as by screws 63" and 68 suitably insulated by piece 63 If the pole piece It is a permanent north pole then the pole piece 2| will be a south pole and when the current flows as above described the head ll of the piston will be a north pole and thusre pelled from pole piece I8 and the similar action of repulsion occurs at the lower end of piston armature ll withthe result that the latter is raised. With the reversal of current in coil 6i and a fiow as indicated by the broken arrows an opposite result occurs, that is, the polarity of the ends of the piston armature is changed andthe piston is attracted or pulled down.

In Figure 9 the current flows in the primary circuit from battery 50 through wires 68 and 69, wire 68 leading to microphone elements 10. Thence current flows through wire II to the pri- .mary 12 of a transformer-and thence by wire 12' to the variable resistance switch 13 and wire 14 I back to battery 50. Branching from wire 6| is wire 69 leading to primary I5 of a second transformer, and thence by wire 18 to microphone elements l1 and thence through the diaphragm [6 (not shown in Figure 9) by proper grounding to the case I and so to wire 18 to variable resistance switch 13 and wire 14 to the battery 50. The cur-. rent generated in the secondary '19 of the transformer, whose primary is 12, is carried by wire 80 to piston coil 24 of the amplifier, thence by wire ill to the secondary l9.

From the secondary 82 of the transformer, whose primary is 15, leads wire 66 which goes to coil 24 beneath cap 9, and thence by wire 63 back to secondary 82.

In Figure 9 the full line arrows indicate current flowing in one direction and the dotted line arrows indicate current flowing in the opposite direction. The action of attraction and repulsion on the piston in the amplifier and on the piston in the ear piece is the same as described in connection with Figure 8.

By means of the rotatable front plate of the earpiece the unit can be adapted to either ear simply by moving the sound tube either forward or backward in relation to the cord which depends normally vertically. The earwire is snapped on in either a right or left position so as to engage the proper groove of either ear lobe.

Furthermore, by means of the combination of rotatable front plate, sound-orifice plate and the offset sound-tube the entire unit is allowed to enter bodily into the earlobe and thus brings the back of the case practically flush with the earlobe. v

A further advantage of the front-plate construction is that the sound emitted by the diaphragm is not throttled by passage through a relatively small hole in the "earpiece cap center and then through a more or less devious passage to the ear canal. By my structure the air above the diaphragm is, during diaphragm activity, given a pressure head and is forced, with increased velocity, directly through the sound tube into the meatus to impinge with increased force against the eardrum.

Another advantage of the front-plate, soundtube and. earwire structure is that the ear is ventilated, the body heat within the ear escapes, the wearer feels a constant sense of comfort and there is no danger of fungus growth and inflammation due to trapping of the internal heat as is common A signal advantage of my motor construction I is that by. the use of diaphragms or vibrators of different thicknesses in combination with variations in piston-armature sizes or Weights accentuation of desired tone-ranges can be brought about to suit the hearing requirements of individual users.

While it is theoretically desirable to have a light vibrating member in the amplifying and earpiece units of hearing aids, it has been found by experiments with my structure herein described that, either with the push-pull effect of transformers in either or both of the circuits, as well as without transformers, a person with a degree of' deafness of 95- percent was able to repeat sentences and phrases whispered at a distance of fifty feet. v Another advantage of my principle in an auricular telephone is the noticeably high degree of the definition characteristic in both speech and music with remarkably large volume on a low current consumption. This makes possible the use of a much smaller battery instead of the usual 3-cell 4.5 volt heavy battery which the user finds so uncomfortable to carry.

Another noteworthy advantage of my novel principle as applied to earphones is that it allows the use of a powerful and efficient earpiece small enough to enter a child's ear, and

be housed in a case no larger than that of the earpiece.

In using my principle it is found that, once the piston head air-gap (top air-gap) is fixed at the most desirable predetermined length, a very delicate adjustment can be made at any time by a slight movement of the lower air-gap adjusting screw which has a very fine thread.

A further desirable feature of my invention is the manner in which it lends itself to rugged construction and consequent durability. For more than eighteen months an experimental set was used by me in trials in cases of deafness. On twooccasions the-transmitter and amplifier E case was pulled accidentally from a table top to the floor, each time by a different user. After each fall the set continued working without ad- Justm'ent and no subsequent adJustment was found necessary.

My invention comprises a vibratory device in which an element, such as a diaphragm, is vi-' brated by a longitudinally movable member within a coil, the device being useful especially for telephonic uses and evenmore especially in devices used as aids for deaf people.

when. the sound waves move the diaphragm 7 this causes longitudinal movement of the piston an exceedingly powerful amplifier unit that can of the mlcrophonic elements, such as 52, 53 or 10, the current is varied and, as above explained,

armature, such as H, with the result of conveying sound waves amplified as in Figures 7 and 9 or directly to the ear of a user as in Figures 3 and 8. The use of said longitudinally movable.

armature within a coil results in greatly increased movement of the vibratory element and consequently more effective action on the plate 38 of Figure 7, or on the air between plate 9 and diaphragm IS in Figure 3' and consequently in the latter case greatly increasing the action on the ear of the user, the sound waves passing through sound channel 9' to the ear of the user.

What I claim is:

1. In an auricular telephone the combination of a motor element; a vibratory element cooperating with the motor element; a case body; a perforat d fixed plate above said vibrating element; a perforated ring cap to clamp said fixed plate to said case body; a rotatable front plate frictionally mounted on said flxed plate; and a sound tube on said rotatable plate. 7

2. In an auricular telephone the combination of a motor element; a vibratory element cooperating with the motor element; a case body; a perforated fixed plate above said vibratory element: a grooved stud riveted to said fixed plate; a perforated ring cap to clamp said fixed plate to said case body; a rotatable front plate mounted frictionally on said fixed plate; a sound tube on said rotatable front plate; and a detachable rubber tipped earwire frictionally mounted on said stud.

JOSEPH G. WHITE. 

